Fix KFunction.javaMethod for property accessors

compiler/testData/codegen/boxWithStdlib/reflection/mapping/propertyAccessors.kt

@@ -0,0 +1,34 @@
+import kotlin.reflect.jvm.*
+import kotlin.test.*
+
+var foo = "foo"
+
+class A {
+    var bar = "bar"
+}
+
+fun box(): String {
+    val fooGetter = ::foo.getter.javaMethod ?: return "Fail fooGetter"
+    assertEquals("foo", fooGetter.invoke(null))
+
+    val fooSetter = ::foo.setter.javaMethod ?: return "Fail fooSetter"
+    fooSetter.invoke(null, "foof")
+    assertEquals("foof", foo)
+
+    assertNull(::foo.getter.javaConstructor)
+    assertNull(::foo.setter.javaConstructor)
+
+
+    val a = A()
+    val barGetter = A::bar.getter.javaMethod ?: return "Fail barGetter"
+    assertEquals("bar", barGetter.invoke(a))
+
+    val barSetter = A::bar.setter.javaMethod ?: return "Fail barSetter"
+    barSetter.invoke(a, "barb")
+    assertEquals("barb", a.bar)
+
+    assertNull(A::bar.getter.javaConstructor)
+    assertNull(A::bar.setter.javaConstructor)
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java

@@ -3237,6 +3237,12 @@ public class BlackBoxWithStdlibCodegenTestGenerated extends AbstractBlackBoxCode
                 doTestWithStdlib(fileName);
             }
 
+            @TestMetadata("propertyAccessors.kt")
+            public void testPropertyAccessors() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/mapping/propertyAccessors.kt");
+                doTestWithStdlib(fileName);
+            }
+
             @TestMetadata("syntheticFields.kt")
             public void testSyntheticFields() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/mapping/syntheticFields.kt");

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KPropertyImpl.kt

@@ -57,6 +57,8 @@ interface KMutablePropertyImpl<R> : KMutableProperty<R>, KPropertyImpl<R> {
     override val setter: Setter<R>
 
     abstract class Setter<R> : KMutableProperty.Setter<R>, KPropertyImpl.Accessor<R>, KCallableImpl<Unit> {
+        abstract override val property: KMutablePropertyImpl<R>
+
         override val name: String get() = "<set-${property.name}>"
 
         override val descriptor: PropertySetterDescriptor by ReflectProperties.lazySoft {

core/reflection.jvm/src/kotlin/reflect/jvm/mapping.kt

@@ -68,7 +68,12 @@ public val KMutableProperty<*>.javaSetter: Method?
  * or `null` if this function is a constructor or cannot be represented by a Java [Method].
  */
 public val KFunction<*>.javaMethod: Method?
-    get() = ((this as? KFunctionImpl)?.caller as? FunctionCaller.Method)?.method
+    get() = when (this) {
+        is KFunctionImpl -> (caller as? FunctionCaller.Method)?.method
+        is KPropertyImpl.Getter<*> -> property.javaGetter
+        is KMutablePropertyImpl.Setter<*> -> property.javaSetter
+        else -> null
+    }
 
 /**
  * Returns a Java [Constructor] instance corresponding to the given Kotlin function,
@@ -76,7 +81,10 @@ public val KFunction<*>.javaMethod: Method?
  */
 @suppress("UNCHECKED_CAST")
 public val <T> KFunction<T>.javaConstructor: Constructor<T>?
-    get() = ((this as? KFunctionImpl)?.caller as? FunctionCaller.Constructor)?.constructor as? Constructor<T>
+    get() = when (this) {
+        is KFunctionImpl -> (caller as? FunctionCaller.Constructor)?.constructor as? Constructor<T>
+        else -> null
+    }